Black soybeans was pre-treated under certain conditions being soaked at 30℃ for 15 h and germination at 25℃ for 72 h.The influence factors impacting extraction yield of soybean isoflavones from black soybean sprouts were explored, and the optimal extraction conditions using microwave-assisted extraction were optimized by single factor and orthogonal experiment, which included solid-liquid ratio, ethanol concentration, microwave-heating time and microwave power.The results showed that the order of different influence factors on yield was microwave-heating time ＞ solid-liquid ratio ＞ microwave power ＞ ethanol concentration.The optimal conditions were as follows: the 1∶25 ratio of solid-liquid, 50% ethanol, extracting for 4 min, microwave power was 450 W.The yield of soybean isoflavones was up to 0.595% under those conditions.